<!doctype html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport"
          content="width=device-width, user-scalable=no, initial-scale=1.0, maximum-scale=1.0, minimum-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>Document</title>
    <style>
        /*html, body {*/
        /*    height: 100%;*/
        /*    margin: 0;*/
        /*}*/

        .content {
            width: 100%;
            background-color: #6F6F6F;
            position: relative;
            height: auto;

        }

        .box {
            width: 100px;
            /*height: 100px;*/
            background-color: #2D6053;
            box-sizing: border-box;
            /*padding: 10px;*/
            /*border: 5px solid #B98C56;*/
            /*margin-top: 20px;*/
            height: 100%;
            position: absolute;
        }
    </style>
</head>
<body>
<div class="content" id="content">
    <div class="box"></div>
</div>

</body>
</html>